Why? He is making a correct decision from the business point of view, it is unclear who will be the replacement CEO, and there are similar layoffs across other tech companies. The board has zero incentive of changing the CEO now.
I think their share price has taken strong corrections due to these decisions. I think that's an incentive for a board to take action?
(I'm purposefully ignoring the ouroborus that is Zuck's control of voting shares that protects him here.)
"I made the decision to significantly increase our investments. Unfortunately, this did not play out the way I expected."
So, keep him to downsize the company and replace him when it's time to start growing again?